1. Field of the Invention
The present invention relates to a beverage container such as a cup designed to be dispensed by an automated vending machine.
2. Description of the Prior Art
Certain food products or beverages such as milkshakes, iced or "slush" drinks and similar preparations require point of sale mixing. Such mixing or stirring is usually quite vigorous and is normally provided by intermittent high speed mixers as in the case of a milkshake machine. Alternatively, the mixing or stirring action is provided by a continuous, low speed machine such as provided by frozen drink or "slush" dispensers.
Because of the peculiar problems associated with these frozen beverages, they are commonly prepared at the point of sale on a demand basis. In other words, the beverage [as served] is not stored for any length of time prior to consumption. This inability to store frozen beverages prior to use is related to food chemistry and the desire for certain unique properties in the product.
Most of the foods that fall into the category of frozen beverages involve the dispersion of fine ice crystals within a matrix of other food products such as milk, cream, syrup, non dairy mixtures and the like. An important characteristic of these frozen beverages is that the dispersion of such fine ice crystals be homogenous throughout the matrix, and that the size of the ice crystals be relatively small and uniform. These parameters generally contribute to favorable "mouth feel" and are judged to be essential in order to elicit consumer acceptance.
While many foods have been successfully sold to consumers via self contained, free standing vending machines, frozen beverages such as milk shakes and other "slush" drinks have not. The primary reason for this exclusion has been the inability to properly mix the beverage after a long period of storage.
It is well known that if beverages that contain water in even small amounts are frozen for any length of time, ice crystals will form. The size of these crystals and their rate of formation is a function of many variables. Some of these factors are the storage temperature, mobility of the fluid phase, time at temperature, and the presence of freezing point depressants such as dissolved sugars, gums, etc., Common experience with ice-cream that is stored for extended periods suggests that even relatively small ice crystals that form in the ice cream are unpleasant. The problem with ice crystal growth in storage is exacerbated when the product contains a greater percentage of water, such as in sherbets or ices.
Milkshakes for example, which are normally made with ice-cream and milk (and other minor additions] cannot be served after storage in a freezer, without a vigorous remixing of the separated components. Storage of a prepared milkshake for even a few hours at temperatures below freezing, results In phase separation of the constituents with the resulting formation of large ice crystals. Storage at temperatures above the freezing point of water is not practical, because the ice-cream melts.
Milkshakes and other frozen beverages including yogurt and iced fruit drinks are not sold by unattended vending machines primarily because of the Ice formation problem. Equipping such machines with stirring or mixing mechanisms is not practical, because of the hygiene issues that are involved. That is, any device that would be inserted into the dispensing cup to adequately stir the contents would have to be scrupulously cleaned after every use, to insure a virtually sterile environment for the food product. The contamination risks involved with such on site cleaning are significant, and the liability exposure due to a malfunctioning cleaning or sterilizing cycle is probably unacceptable.
Individual, hygienic packaging of food products is a well developed art, and all types of food products are sold in vending machine. Unit packaging of ice-cream has been very successful, and when stored at sufficiently low temperature the product will keep for many weeks. Other products, in aseptic packaging, will keep for many weeks at temperatures just above the freezing point, which makes their storage far more cost efficient. Obviously, the cost of refrigeration is a direct function of the requisite storage temperature, and the ability to raise the safe storage temperature a few degrees has a direct impact on energy costs.
There are containers in the prior art such as that disclosed in U.S. Pat. No. 4,408,690 to Ferrero, but now are known which can accommodate such frozen products.